Curable silicone compositions, methods and articles made therefrom

ABSTRACT

A silicone composition that includes at least one functionalized polydiorganosiloxane, at least one cure catalyst, at least one reactive diluant, and at least one thermally conductive filler is provided in the present invention. Further embodiments of the present invention include a method for substantially increasing the thermal conductivity of a silicone composition and a thermal interface material containing the aforementioned silicone composition.

BACKGROUND OF THE INVENTION

[0001] The present invention is related to silicone compositions. Moreparticularly, the present invention is related to low viscosity, curablepolydiorganosiloxane compositions.

[0002] Dispensable materials that can cure and give high thermalconductivity are typically used in the electronics industry. Currently,there are two classes of cured articles used as thermally conductivesinks. Sakamoto et al., Japanese Patent No. 05117598, discuss highlyfilled matrices that are cured to make a pad. The pad can be cut andphysically placed in an electronic device. Toya, Japanese Patent No.02097559, discusses a filled matrix that is dispensed and cured inplace. The dispensable approach requires that the material have aviscosity that is low enough such that the material can be forcedthrough an orifice for rapid manufacture of many parts. However, thefinal cured product must have a sufficiently high thermal conductivity.

[0003] There remains a need to find a material that has a sufficientlylow viscosity such that it can be rapidly placed on a small device withhigh power requirements. The high power requirement needs a way toremove more heat. This requirement necessitates a thermally conductivematerial. Thus, dispensable, curable, and high thermally conductivematerials are constantly being sought.

BRIEF SUMMARY OF THE INVENTION

[0004] The present invention provides a silicone composition comprisinga curable adhesive formulation which comprises

[0005] (A) a functionalized polydiorganosiloxane having the generalformula:

(R¹)_(3-p)R² _(p)SiO [(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q)

[0006] wherein R² is independently at each occurrencevinylcyclohexeneoxy, silane, epoxy, glycidoxy, acryloxy, imide,urethane, vinyl, or combinations thereof; R1 is independently at eachoccurrence a C₁₋₈ alkyl radical, phenyl radical, vinyl radical, orcombination thereof; “p” is 0 or 1; “q” is 0 or 1; “m”+“n” has a valuesufficient to provide a polydiorganosiloxane with an initial viscosityin a range between about 100 centipoise and about 50,000 centipoise at25° C.;

[0007] (B) at least one reactive diluant;

[0008] (C) at least one cure catalyst; and

[0009] (D) at least one thermally conductive filler;

[0010] wherein the total silicone composition has a viscosity in a rangebetween about 10,000 centipoise and about 250,000 centipoise at 25° C.before cure.

[0011] The present invention further provides a method for increasingthe thermal conductivity of a silicone composition comprising:

[0012] (A) providing at least one functionalized polydiorganosiloxanehaving the general formula:

(R¹)_(3-p)R² _(p)SiO[(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q)

[0013] wherein R² is independently at each occurrencevinylcyclohexeneoxy, silane, epoxy, glycidoxy, acryloxy, imide,urethane, vinyl, or combinations thereof; R¹ is independently at eachoccurrence a C₁₋₈ alkyl radical, phenyl radical, vinyl radical, orcombination thereof; “p” is 0 or 1; “q” is 0 or 1; “m”+“n” has a valuesufficient to provide a polydiorganosiloxane with an initial viscosityin a range between about 100 centipoise and about 50,000 centipoise at25° C.;

[0014] combining into the polydiorganosiloxane at least one thermallyconductive filler in a range between about 60% by weight and about 95%by weight of the total silicone composition;

[0015] combining into the polydiorganosiloxane at least one diluant; and

[0016] combining into the polydiorganosiloxane at least one curecatalyst wherein the total silicone composition has a viscosity in arange between about 10,000 centipoise and about 250,000 centipoise at25° C. before cure.

[0017] In yet a further embodiment of the present invention, there isprovided a thermal interface material comprising:

[0018] (A) at least one polydiorganosiloxane having the general formula:

(R¹)_(3-p)R² _(p)SiO[(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q)

[0019] wherein R² is independently at each occurrencevinylcyclohexeneoxy, silane, epoxy, glycidoxy, acryloxy, imide,urethane, vinyl, or combinations thereof; R¹ is independently at eachoccurrence a C₁₋₈ alkyl radical, phenyl radical, vinyl radical, orcombination thereof; “p” is 0 or 1; “q” is 0 or 1; “m”+“n” has a valuesufficient to provide a polydiorganosiloxane with an initial viscosityin a range between about 100 centipoise and about 50,000 centipoise at25° C.;

[0020] (B) at least one reactive diluant;

[0021] (C) at least one cure catalyst; and

[0022] (D) at least one thermally conductive filler;

[0023] wherein the thermal interface material provides adhesion to atleast one substrate.

DETAILED DESCRIPTION OF THE INVENTION

[0024] It has been found that the use of at least one functionalizedpolydiorganosiloxane, at least one reactive diluant, at least one curecatalyst, and at least one thermally conductive filler provides aformulation with a low viscosity of the total silicone compositionbefore cure and whose cured parts have a high thermal conductivity.“High thermal conductivity” as used herein refers to a cured totalsilicone composition with a thermal conductivity greater than about 1.5Watts per meter per degree Kelvin (W/mK). “Low viscosity of the totalsilicone composition before cure” typically refers to a viscosity of thecomposition in a range between about 10,000 centipoise and about 250,000centipoise and preferably, in a range between about 20,000 centipoiseand about 100,000 centipoise at 25° C. before the silicone compositionis cured. “Cured” as used herein refers to a total silicone compositionwith reactive groups wherein in a range between about 50% and about 100%of the reactive groups have reacted.

[0025] The functionalized polydiorganosiloxane has the general formula(I),

(R¹)_(3-p)R² _(p)SiO[(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q)  (I)

[0026] wherein R² is independently at each occurrencevinylcyclohexeneoxy, silane, epoxy, glycidoxy, acryloxy, imide,urethane, vinyl, or combination thereof; R¹ is independently at eachoccurrence a C₁₋₈ alkyl radical, phenyl radical, vinyl radical, orcombination thereof; “p” is 0 or 1; “q” is 0 or 1; “m”+“n” has a valuesufficient to provide a polydiorganosiloxane with an initial viscosityin a range between about 100 centipoise and about 50,000 centipoise at25° C. and a functional content in a range between about 1% by weightand about 10% by weight of the functionalized polydiorganosiloxane.Radicals represented by R¹ are preferably C₁₋₄ alkyl radicals and morepreferably, methyl. Typically, the functionalized polydiorganosiloxaneis present in a range between about 0.5% by weight and about 5% byweight of the total silicone composition, and more typically in a rangebetween about 1% by weight and about 2% by weight of the total siliconecomposition.

[0027] Additionally, a reactive organic diluant may be added to thesilicone composition to decrease the viscosity of the composition.Examples of diluants include, but are not limited to, styrene monomerssuch as tert-butyl styrene (t-Bustyrene), (meth)acrylate monomers suchas methylmethacrylate and hexanedioldiacrylate, methacryloxy-containingmonomers such as methacryloxypropyltrimethoxysilane, epoxy-containingmonomers such as biscyclohexaneoxyethylenetetramethylsiloxane,glycidoxy-containing monomers such as glycidoxypropyltrimethoxysilane,hydride-stopped polydimethylsiloxanes, and vinyl ethers. It is to beunderstood that (meth)acrylate includes both acrylates andmethacrylates. Vinyl ethers include mono-, di-, and poly-vinyl etherscontaining carbon atoms in a range between about 2 and about 20. Thepreferred reactive diluants are methacryloxypropyltrimethoxysilane andvinyl ethers. The mixture of the diluant and the functionalizedpolydiorganosiloxane lowers the viscosity, which allows for higherloading of thermally conductive filler. The amount of thermallyconductive filler in the silicone composition is directly proportionalto the thermal conductivity. Thus, the higher the amount of thermallyconductive filler in the silicone composition, the greater the thermalconductivity of the silicone composition.

[0028] The thermally conductive fillers in the present invention includeall common thermally conductive solids. Thermally conductive fillers inthe present invention include, for example, forms of silver, gold,copper, nickel, platinum group metals, and combinations thereof. Silveris the preferred thermally conductive filler. Examples of thermallyconductive silver include, but are not limited to, silver powders,silver flakes, colloidal silver, and combinations thereof. Furtherexamples of thermally conductive fillers include, but are not limitedto, aluminum oxide, aluminum nitride, boron nitride, diamond, magnesiumoxide, zinc oxide, and zirconium oxide. The filler is present in a rangebetween about 60% by weight and about 95% by weight of the totalsilicone composition, more typically the filler is present in a rangebetween about 75% by weight and about 85% by weight of the totalsilicone composition.

[0029] Inhibitors such as esters of maleic acid (e.g. diallylmaleate,dimethylmaleate), acetylenic alcohols (e.g., 3,5 dimethyl-1-hexyn-3-oland 2 methyl-3-butyn-2-ol), amines, andtetravinyltetramethylcyclotetrasiloxane and mixtures thereof can also beemployed when used in an effective amount which is typically in a rangebetween about 0.01% by weight and about 1% by weight of the totalsilicone composition.

[0030] Adhesion promoters can also be employed such astrialkoxyorganosilanes (e.g. γ-aminopropyltrimethoxysilane,glycidoxypropyltrimethoxysilane, bis(trimethoxysilylpropyl)fumarate)used in an effective amount which is typically in a range between about0.01% by weight and about 1% by weight of the total siliconecomposition. The preferred adhesion promoter isbis(trimethoxysilylpropyl)fumarate.

[0031] Cure catalysts may also be present in the total siliconecomposition that accelerates curing of the total silicone composition.Typically, the catalyst is present in a range between about 10 parts permillion (ppm) and about 10% by weight of the total silicone composition.Examples of cure catalysts include, but are not limited to, peroxidecatalysts such as t-butylperoxybenzoate, onium catalysts such asbisaryliodonium salts (e.g. bis(dodecylphenyliodoniumhexafluoroantimonate, (octyloxyphenyl, phenyl)iodoniumhexafluoroantimonate, bisaryliodoniumtetrakis(pentafluorophenyl)borate), triarylsulphonium salts, andplatinum catalysts. Preferably, the catalyst is a bisaryliodonium salt.Curing typically occurs at a temperature in a range between about 50° C.and about 175° C., more typically in a range between about 100° C. andabout 150° C., at a pressure in a range between about 1 atmosphere (atm)and about 5 tons pressure per square inch, more typically in a rangebetween about 1 atmosphere and about 100 pounds per square inch (psi).In addition, curing may typically occur over a period in a range betweenabout 5 minutes and about 1 hour, and more typically in a range betweenabout 15 minutes and about 45 minutes.

[0032] The composition of the present invention may by hand mixed butalso can be mixed by standard mixing equipment such as dough mixers,chain can mixers, planetary mixers, and the like.

[0033] The blending of the present invention can be performed in batch,continuous, or semi-continuous mode. With a batch mode reaction, forinstance, all of the reactant components are combined and reacted untilmost of the reactants are consumed. In order to proceed, the reactionhas to be stopped and additional reactant added. With continuousconditions, the reaction does not have to be stopped in order to addmore reactants.

[0034] Thermally conductive materials as described in the presentinvention are dispensable and have utility in devices in electronicssuch as computers or in any device that generates heat and where thedevice requires the heat to be efficiently removed. The thermallyconductive material is typically used as a thermal interface materialthat provides adhesion to at least one substrate such as silicon,gallium arsenide (GaAs), copper, nickel, and the like.

[0035] In order that those skilled in the art will be better able topractice the invention, the following examples are given by way ofillustration and not by way of limitation.

EXAMPLE 1

[0036] A base siloxane was prepared by combining as follows: 20 grams(g) of GE Silicones vinyl-stopped polydimethylsiloxane with an averagedegree of polymerization of about 20, 5 g of GE Silicones blend of a1000 centipoise (cps) vinyl-stopped polydimethylsiloxane and MDViQresin, 1.7 g of GE Silicones MHQ crosslinker containing about 1 wt %hydrogen, 9.1 g of Gelest, Inc. intermediate DMSH03 which is H-stoppedpolydimethylsiloxane with an average degree of polymerization of 5.1 and0.85 g of catalyst. The catalyst was pre-made and was composed of 87milligrams (mg) of GE Silicones platinum catalyst, 4.3 g of GE Siliconesadhesion promoter, 1.3 g of dibutylmaleate, 2.16 g of triallylisocyanurate, and 2.16 g of glycidoxypropyltrimethoxysilane.

EXAMPLE 2

[0037] The base siloxane in example 1 (9 g) was combined with silver(38.4 g, 80/20 w/w silver powder/flake mixture of 80 parts Technicsilver powder 17-253 and 20 parts Ames Goldsmith 1024 silver flake togive a final formulation of 81% by weight in silver). Thesilver-siloxane had a viscosity of 50,400 cps at 0.5 rotations perminute (rpm) as measured by a Brookfield Model DV-II Cone & PlateViscometer using a #52 cone. The mixture was cured at 150° C. for 30minutes and had a thermal conductivity of 5.17 W/mK (5.42 W/mK onrepeat) as measured by a Holometrix TCA instrument.

EXAMPLE 3

[0038] The formulation prepared in Example 2 was repeated except thatonly silver flake was used (i.e. no powder was used). The initialviscosity was 80,000 cps. The thermal conductivity was measured for twosamples. In one reading, a value of 16.5 W/mK was obtained and in thesecond reading, a value of 7.15 W/mK was obtained.

EXAMPLE 4

[0039] A base formulation was prepared composed of a 50/50 w/w mixtureof Gelest Inc. intermediate DMSE21 (a glycidoxy-on-chainpolydimethylsiloxane copolymer) and 1,4-divinyloxybutane. The 50/50mixture above was then combined with 2% by weight of GE Silicones UVphotoinitiator UV9380c. To the above polymer/catalyst mixture was addedthe silver powder/flake mixture of 80 parts Technic silver powder 17-253and 20 parts Ames Goldsmith 1024 silver flake to give a finalformulation 81% by weight in silver. The initial viscosity was 74,000cps and the thermal conductivity of the cured formulation was 5.24 W/mK(a second sample was made and gave a thermal conductivity reading of 7.5W/mK).

EXAMPLE 5

[0040] A base formulation was prepared composed of 50/50 w/w mixture ofGelest Inc. intermediate UMS 182 (80-120 cps acryloxy-on-chainpolydimethylsiloxane copolymer) and methacryloxypropyltrimethoxysilane.The 50/50 polymer mixture above was combined with 2% by weight oft-butylperoxybenzoate. An 80/20 silver powder/flake mixture of Example 4was combined with the polymer catalyst mixture to make a formulationthat was 81% by weight silver. The initial viscosity was 47,000 cps andthe thermal conductivity of the cured formulation was 2.69 W/mK.

EXAMPLE 6

[0041] The polymer and silver formulation was prepared as in example 5except that in place of the t-butylperoxybenzoate catalyst, UV 9380c asin example 4 was used. The formulation was made two times: once with aviscosity of 41,000 cps and once with a viscosity of 43,000 cps. Theformulations were cured at 150° C. for 30 minutes in a Carver press at5000 pounds per square inch. The thermal conductivity was greater than 6W/mK (triplicate measurements) for both formulations.

[0042] While embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and the scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustration and not limitation.

What is claimed is:
 1. A silicone composition comprising a curableadhesive formulation which comprises (A) a functionalizedpolydiorganosiloxane having the general formula: (R¹)_(3-p)R² _(p)SiO[(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q) wherein R² isindependently at each occurrence vinylcyclohexeneoxy, silane, epoxy,glycidoxy, acryloxy, imide, urethane, vinyl, or combinations thereof; R¹is independently at each occurrence a C₁₋₈ alkyl radical, phenylradical, vinyl radical, or combination thereof; “p” is 0 or 1; “q” is 0or 1; “m”+“n” has a value sufficient to provide a polydiorganosiloxanewith an initial viscosity in a range between about 100 centipoise andabout 50,000 centipoise at 25° C.; (B) at least one reactive diluant;(C) at least one cure catalyst; and (D) at least one thermallyconductive filler; wherein the total silicone composition has aviscosity in a range between about 10,000 centipoise and about 250,000centipoise at 25° C. before cure.
 2. The silicone composition inaccordance with claim 1, wherein the R² is an acryloxy group.
 3. Thesilicone composition in accordance with claim 1, wherein R1 is a methylgroup.
 4. The silicone composition in accordance with claim 1, whereinthe thermally conductive filler comprises silver, gold, copper,platinum, nickel, aluminum oxide, aluminum nitride, boron nitride,diamond, magnesium oxide, zinc oxide, zirconium oxide, or combinationsthereof.
 5. The silicone composition in accordance with claim 4, whereinthe thermally conductive filler comprises silver.
 6. The siliconecomposition in accordance with claim 1, wherein at least one filler ispresent in a range between about 60% by weight and about 95% by weightof the total silicone composition.
 7. The silicone composition inaccordance with claim 1, wherein the diluant comprisestert-butyl-styrene, methacryloxypropyltrimethoxysilane,methylmethacrylate, hexanedioldiacrylate,glycidoxypropyltrimethoxysilane, vinyl ether, or combinations thereof.8. The silicone composition in accordance with claim 7, wherein thediluant comprises methacryloxypropyltrimethoxysilane.
 9. The siliconecomposition in accordance with claim 7, wherein the diluant comprisesvinyl ether.
 10. The silicone composition in accordance with claim 1,wherein the diluant is present in a range between about 1% by weight andabout 20% by weight of the total silicone composition.
 11. The siliconecomposition in accordance with claim 1, wherein the cured compositionprovides a thermal conductivity greater than about 1.5 W/mK.
 12. Thesilicone composition in accordance with claim 1, wherein the curedcomposition provides adhesion to at least one substrate.
 13. Thesilicone composition in accordance with claim 12, wherein the substratecomprises silicon.
 14. The silicone composition in accordance with claim1, wherein the curing catalyst comprises peroxide, onium salt, platinumcatalyst, or combinations thereof.
 15. The silicone composition inaccordance with claim 14, wherein the curing catalyst comprisesbisaryliodonium salt.
 16. The silicone composition in accordance withclaim 1, wherein the catalyst is present in a range between about 10parts per million and about 10% by weight of the total siliconecomposition.
 17. The silicone composition in accordance with claim 1,which further comprises an adhesion promoter. 18 The siliconecomposition in accordance with claim 17, wherein the adhesion promotercomprises trialkoxyorganosilanes.
 19. The silicone composition inaccordance with claim 18, wherein the trialkoxyorganosilane isγ-aminopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane,bis(trimethoxysilylpropyl)fumarate, or combinations thereof.
 20. Thesilicone composition in accordance with claim 19, wherein thetrialkoxyorganosilane is bis(trimethoxysilylpropyl)fumarate. 21 Thesilicone composition in accordance with claim 17, wherein the adhesionpromoter is present in a range between about 0.01% by weight and about1% by weight of the total silicone composition.
 22. The siliconecomposition in accordance with claim 1, which is cured.
 23. A siliconecomposition comprising a curable adhesive formulation which comprises(A) a polydiorganosiloxane having the general formula: (R¹)_(3-p)R²_(p)SiO [(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q) wherein R² isacryloxy group, R¹ is methyl group, “p” is 0 or 1, “q” is 0 or 1,“m”+“n” has a value sufficient to provide a polydiorganosiloxane with aninitial viscosity in a range between about 100 centipoise and about50,000 centipoise at 25° C.; (B) at least one thermally conductivefiller comprising silver; (C) at least one diluant comprisingmethacryloxypropyltrimethoxysilane; (D) at least one curing catalystcomprising bisaryliodonium salt; and (E) optionally, at least oneadhesion promoter comprising a bis(trimethoxysilylpropyl)fumarate;wherein the total silicone composition has a viscosity in a rangebetween about 10,000 centipoise and about 250,000 centipoise at 25° C.before cure.
 24. A method for substantially increasing the thermalconductivity of a silicone composition comprising: providing at leastone functionalized polydiorganosiloxane wherein the polydiorganosiloxanehas the general formula: (R¹)_(3-p)R² _(p)SiO[(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q) wherein R² isindependently at each occurrence vinylcyclohexeneoxy, silane, epoxy,glycidoxy, acryloxy, imide, urethane, vinyl, or combinations thereof; R¹is independently at each occurrence a C₁₋₈ alkyl radical, phenylradical, vinyl radical, or combination thereof; “p” is 0 or 1; “q” is 0or 1; “m”+“n” has a value sufficient to provide a polydiorganosiloxanewith an initial viscosity in a range between about 100 centipoise andabout 50,000 centipoise at 25° C.; combining into thepolydiorganosiloxane at least one thermally conductive filler in a rangebetween about 60% by weight and about 95% by weight of the totalsilicone composition; combining into the polydiorganosiloxane at leastone diluant; and combining into the polydiorganosiloxane at least onecure catalyst wherein the total silicone composition has a viscosity ina range between about 10,000 centipoise and about 250,000 centipoise at25° C. before cure.
 25. The method in accordance with claim 24, whereinthe R² is an acryloxy group.
 26. The method in accordance with claim 24,wherein R¹ is a methyl group.
 27. The method in accordance with claim24, wherein the thermally conductive filler comprises silver, gold,copper, platinum, nickel, aluminum oxide, aluminum nitride, boronnitride, diamond, magnesium oxide, zinc oxide, zirconium oxide, orcombinations thereof.
 28. The method in accordance with claim 27,wherein the thermally conductive filler comprises silver.
 29. The methodin accordance with claim 24, wherein at least one filler is present in arange between about 60% by weight and about 95% by weight of the totalsilicone composition.
 30. The method in accordance with claim 24,wherein the diluant comprises tert-butyl-styrene,methacryloxypropyltrimethoxysilane, methylmethacrylate,hexanedioldiacrylate, glycidoxypropyltrimethoxysilane, vinyl ether, orcombinations thereof.
 31. The method in accordance with claim 30,wherein the diluant comprises methacryloxypropyltrimethoxysilane. 32.The method in accordance with claim 30, wherein the diluant comprisesvinyl ether.
 33. The method in accordance with claim 24, wherein thediluant is present in a range between about 1% by weight and about 20%by weight of the total silicone composition.
 34. The method inaccordance with claim 24, wherein the cured composition provides athermal conductivity greater than about 1.5 W/mK.
 35. The method inaccordance with claim 24, wherein the cured composition providesadhesion to at least one substrate.
 36. The method in accordance withclaim 30, wherein the substrate comprises silicon.
 37. The method inaccordance with claim 24, wherein the curing catalyst comprisesperoxide, onium salt, platinum catalyst, or combinations thereof. 38.The method in accordance with claim 37, wherein the curing catalystcomprises bisaryliodonium salt.
 39. The method in accordance with claim24, wherein the catalyst is present in a range between about 10 partsper million and about 10% by weight of the total silicone composition.40. The method in accordance with claim 24, further comprising the stepof combining into the polydiorganosiloxane at least one adhesionpromoter.
 41. The method in accordance with claim 40, wherein theadhesion promoter comprises trialkoxyorganosilanes.
 42. The method inaccordance with claim 41, wherein the trialkoxyorganosilane isγ-aminopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane,bis(trimethoxysilylpropyl)fumarate, or combinations thereof.
 43. Themethod in accordance with claim 42, wherein the trialkoxyorganosilane isbis(trimethoxysilylpropyl)fumarate.
 44. The silicone composition inaccordance with claim 40, wherein the adhesion promoter is present in arange between about 0.01% by weight and about 1% by weight of the totalsilicone composition.
 45. A method for increasing the thermalconductivity of a silicone composition comprising: providing at leastone polydiorganosiloxane having the general formula: (R¹)_(3-p)R²_(p)SiO [(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q) wherein R² isacryloxy group, R¹ is methyl group, “p” is 0 or 1, “q” is 0 or 1,“m”+“n” has a value sufficient to provide a polydiorganosiloxane with aninitial viscosity in a range between about 100 centipoise and about50,000 centipoise at 25° C.; combining into the polydiorganosiloxane atleast one thermally conductive filler in a range between about 60% byweight and about 95% by weight of the total silicone composition whereinthe filler comprises silver; combining into the polydiorganosiloxane atleast one diluant wherein the diluant comprisesmethacryloxypropyltrimethoxysilane; combining into thepolydiorganosiloxane at least one cure catalyst wherein the curecatalyst comprises bisaryliodonium salt; and optionally combining intothe polydiorganosiloxane at least one adhesion promoter comprisingbis(trimethoxysilylpropyl)fumarate wherein the total siliconecomposition provides a viscosity in a range between about 10,000centipoise and about 250,000 centipoise at 25° C. before cure and thecured composition provides a thermal conductivity greater than about 1.5W/mK.
 46. A thermal interface material comprising: (A) (A) at least onepolydiorganosiloxane having the general formula: (R¹)_(3-p)R² _(p)SiO[(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q) wherein R² isindependently at each occurrence vinylcyclohexeneoxy, silane, epoxy,glycidoxy, acryloxy, imide, urethane, vinyl, or combinations thereof; R¹is independently at each occurrence a C₁₋₈ alkyl radical, phenylradical, vinyl radical, or combination thereof; p is 0 or 1; “q” is 0 or1; “m”+“n” has a value sufficient to provide a polydiorganosiloxane withan initial viscosity in a range between about 100 centipoise and about50,000 centipoise at 25° C.; (B) at least one reactive diluant; (C) atleast one cure catalyst; and (D) at least one thermally conductivefiller; wherein the thermal interface material provides adhesion to atleast one substrate.
 47. The thermal interface material in accordancewith claim 46, wherein the R² is an acryloxy group.
 48. The thermalinterface material in accordance with claim 46, wherein R¹ is a methylgroup.
 49. The thermal interface material in accordance with claim 46,wherein the thermally conductive filler comprises silver, gold, copper,platinum, nickel, aluminum oxide, aluminum nitride, boron nitride,diamond, magnesium oxide, zinc oxide, zirconium oxide, or combinationsthereof.
 50. The thermal interface material in accordance with claim 49,wherein the thermally conductive filler comprises silver.
 51. Thethermal interface material in accordance with claim 46, wherein at leastone filler is present in a range between about 70% by weight and about95% by weight of the total silicone composition.
 52. The thermalinterface material in accordance with claim 46, wherein the diluantcomprises tert-butyl-styrene, methacryloxypropyltrimethoxysilane,methylmethacrylate, hexanedioldiacrylate,glycidoxypropyltrimethoxysilane, vinyl ether, or combinations thereof.53. The thermal interface material in accordance with claim 52, whereinthe diluant comprises methacryloxypropyltrimethoxysilane.
 54. The methodin accordance with claim 52, wherein the diluant comprises vinyl ether.55. The thermal interface material in accordance with claim 46, whereinthe diluant is present in a range between about 1% by weight and about20% by weight of the total silicone composition.
 56. The thermalinterface material in accordance with claim 46, wherein the curedcomposition provides a thermal conductivity greater than about 1.5 W/mK.57. The thermal interface material in accordance with claim 46, whereinthe substrate comprises silicon.
 58. The thermal interface material inaccordance with claim 46, wherein the cure catalyst comprises peroxide,onium salt, platinum catalyst, or combinations thereof.
 59. The thermalinterface material in accordance with claim 58, wherein the curecatalyst comprises bisaryliodonium salt.
 60. The thermal interfacematerial in accordance with claim 46, wherein the catalyst is present ina range between about 10 parts per million and about 10% by weight ofthe total silicone composition.
 61. The thermal interface material inaccordance with claim 46, which further comprises at least one adhesionpromoter.
 62. The thermal interface material in accordance with claim61, wherein the adhesion promoter comprises trialkoxyorganosilanes. 63.The thermal interface material in accordance with claim 62, wherein thetrialkoxyorganosilane is γ-aminopropyltrimethoxysilane,glycidoxypropyltrimethoxysilane, bis(trimethoxysilylpropyl)fumarate, orcombinations thereof.
 64. The thermal interface material in accordancewith claim 63, wherein the trialkoxyorganosilane isbis(trimethoxysilylpropyl)fumarate.
 65. The thermal interface materialin accordance with claim 61, wherein the adhesion promoter is present ina range between about 0.01% by weight and about 1% by weight of thetotal silicone composition.
 66. A thermal interface material comprising:(A) at least one polydiorganosiloxane having the general formula:(R¹)_(3-p)R² _(p)SiO [(R¹)₂SiO]_(m)[R¹R²SiO]_(n)Si(R¹)_(3-q)R² _(q)wherein R² is acryloxy group, R¹ is methyl group, “p” is 0 or 1, “q” is0 or 1, “m”+“n” has a value sufficient to provide a polydiorganosiloxanewith an initial viscosity in a range between about 100 centipoise andabout 50,000 centipoise at 25° C.; (B) at least one thermally conductivefiller comprising silver; (C) at least one diluant comprisingmethacryloxypropyltrimethoxysilane; (D) at least one cure catalystwherein the cure catalyst comprises bisaryliodonium salt; and (E)optionally, at least one adhesion promoter comprisingbis(trimethoxysilylpropyl)fumarate wherein the thermal interfacematerial following curing of the silicone composition provides a thermalconductivity greater than about 1.5 W/mK.